blob: 9676b5f52c6cf8b8da4937f713a7de007c3df9bc
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Utility routines. |
4 | * |
5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
8 | */ |
9 | |
10 | #include "libbb.h" |
11 | #include <mntent.h> |
12 | |
13 | /* |
14 | * Given a block device, find the mount table entry if that block device |
15 | * is mounted. |
16 | * |
17 | * Given any other file (or directory), find the mount table entry for its |
18 | * filesystem. |
19 | */ |
20 | struct mntent* FAST_FUNC find_mount_point(const char *name, int subdir_too) |
21 | { |
22 | struct stat s; |
23 | FILE *mtab_fp; |
24 | struct mntent *mountEntry; |
25 | dev_t devno_of_name; |
26 | bool block_dev; |
27 | |
28 | if (stat(name, &s) != 0) |
29 | return NULL; |
30 | |
31 | devno_of_name = s.st_dev; |
32 | block_dev = 0; |
33 | /* Why S_ISCHR? - UBI volumes use char devices, not block */ |
34 | if (S_ISBLK(s.st_mode) || S_ISCHR(s.st_mode)) { |
35 | devno_of_name = s.st_rdev; |
36 | block_dev = 1; |
37 | } |
38 | |
39 | mtab_fp = setmntent(bb_path_mtab_file, "r"); |
40 | if (!mtab_fp) |
41 | return NULL; |
42 | |
43 | while ((mountEntry = getmntent(mtab_fp)) != NULL) { |
44 | /* rootfs mount in Linux 2.6 exists always, |
45 | * and it makes sense to always ignore it. |
46 | * Otherwise people can't reference their "real" root! */ |
47 | if (ENABLE_FEATURE_SKIP_ROOTFS && strcmp(mountEntry->mnt_fsname, "rootfs") == 0) |
48 | continue; |
49 | |
50 | if (strcmp(name, mountEntry->mnt_dir) == 0 |
51 | || strcmp(name, mountEntry->mnt_fsname) == 0 |
52 | ) { /* String match. */ |
53 | break; |
54 | } |
55 | |
56 | if (!(subdir_too || block_dev)) |
57 | continue; |
58 | |
59 | /* Is device's dev_t == name's dev_t? */ |
60 | if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == devno_of_name) |
61 | break; |
62 | /* Match the directory's mount point. */ |
63 | if (stat(mountEntry->mnt_dir, &s) == 0 && s.st_dev == devno_of_name) |
64 | break; |
65 | } |
66 | endmntent(mtab_fp); |
67 | |
68 | return mountEntry; |
69 | } |
70 |